Propeller



E. P. CONWAY.

PROPELLER. APPLICATION HLED MAR.31. 1919.

Patented Jan. 25, 1921.

IN VEN TOR.

EZTORNEY.

Ma's PETERS .n: um E c,

UNITED srA'res ZEIIJX7V'..4.R1) IE. CDNWAY, O1? "WATERBURY, CONNECTICUT.

PROPELLER.

Specification of Letters Patent.

Patented Jan. 25, 1921.

Application filed March 31, 1919. Serial No. 286,525.

To all whom it may concern."

Be it known that I, Enwnno P. CONWAY, a citizen of the United States, and a resident of lVaterbury, in the county of New Haven and dtate of Connecticut, have invented a new and Improved Propeller, of which the following is a specification.

My invention relates to the class of devicesabove described, and an object of the invention, among others, is to increase ciency of the propeller by a construction of blade that will cause the propeller to have increased hold upon the medium in which it may be rotated.

One form of device embodying my invention and in the construction and use of which the objects herein set out, as well as others, may be attained, is illustrated in the accompanying drawings, in which Figure 1 is a back view of my improved propeller when looking in the direction indicated by the arrows in Figs. 2 and 3.

Fig. 2 is an edge view of the same when looking in the direction indicated by the dotted line 2-2 and arrows in Fig. 1.

Fig. 3 is an end view of the device.

Fig. i is a View in section through the propeller on a plane denoted by dotted line H of Fig.

Fig. 5 is a View in section through the propeller on plane denoted by dotted line 55 of Fig. 2.

In the accompanying drawings the numeral 5 denotes the hub of my improved propeller having blades 6 projecting there from in opposite directions and they may be inclined at an angle to the plane of rotation, as is common in devices of this class.

Prior to my invention the blades of propellers have commonly been plain and smooth from the hub to the tip with a re suit that the air slips toward the end of the blade by centrifugal action and consequently the hold ofthe blade upon the air or other medium in whichit may be rotating is not so great as it would be did this outward movement of the medium by centrifugal action not take place, the term holding denoting the frictional resistance of the blade to movement of the fluid lengthwise of the blade, whereby diminished rarety of the air within the sphere of rotation of the blade is prevented.

To overcome this result and increase the hold of the blades of the propeller on the medium in which they rotate, I provide grooves or depressions '7 extending crosswise of the blades and located on the backs thereof, these depressions, in their preferred torm, being narrower at their front edges, or that edge of the blade in advance when the propeller is rotated, the direction of rotation being indicated by the arrow in Fig. 1. The width of the depressions are illcreasedpreferably on curved lines, and said depressions are also formed on curved lines that are substantially uniform onopposite sides of a line extending centrally through thedepressions from end to end. The onposlte sides of the blades are curved to a greater or lesser degree so that the depth of the depressions from front to rear is increased, although the formation of the depressions are such that the bottoms thereof are formed on straight lines from one end to the other thereof, that is, there is no curve in the depressions in a direction crosswise of the blades. This formation of the bot toms of the depressions on straight lines lengthwise thereof presents no greater obstruction to the movement of the blade through the medium upon which it is acting than that inclination of the blade required to exert the proper hold upon such medium. However, my invention is not limited in its scope to a depression or groove in the propeller of the specific shape herein shown and described, and they may be varied therefrom to some extent and yet embody the invention and in accordance with the provisions of the patent statutes, I have described the principles of operation of my invention, together with the device which I new consider to represent the best embodiment thereof; but I desire to have it understood that the device shown is only illustrative, and that the invention may be carried out by other means.

I claim- 1. A propeller including a hub, blades on tending therefrom and smooth on one side, i

and a depression extending across each blade on the opposite side and increasing in area from the front to the rear edge thereof, the dimensions of said depression being substantially equal on opposite sides of a line passing centrally therethrough, the bottom line of said depressions being straight and tangent to the curve of rotation thereof.

2. A propeller including a hub, blades eX-- tending therefrom, and a series of depressions arranged lengthwise of the blades, all

of said depressions increasing in area from the front to the rear edges of the blades,.

tom lines of said depressions being straight and parallel and tangent to the curve of rotation thereof.

' 3. A propeller including a hub, blades eX- tending therefrom and angularly disposed with respect to the plane of rotation thereof, and a series of depressions arranged lengthwise of the blades, each depression er:- tending' crosswise thereof and having its bottom formed on straight lines lengthwise thereof and crosswise of theiblade and tan gent to the curve of rotation and all ofsaid depressions increasing in area from the front to the rear.'

4. A propeller including a hub, blades extending therefrom and smooth on one side, and a series of depressions extending across each blade on the side opposite the smooth side and increasing in area from the front to the rear edge'thereof, said depressions being curved lengthwise of the blade and substantially equal on opposite sides of a line passing centrally therethrough, the bottom line of said depressions being straight and tangent to the curve of rotationthereof.

5. A propeller including a hub, blades ex tending therefrom and smooth on one side,

and depressions extending across the blades, said depressions beingeurved lengthwise of the blade and increasing in width from the front to the rear and in depth also from the front to the rear edge, the bottom line of said depressions being straight and tangent to the curve of rotation thereof.

' EDWARD P. CONWAY. 

